Steve Mould The Weird Science Hidden Inside Canadian Money

[Steve Mould:]Source: LYBIO.net
I’m here in Canada for the holidays and you may already know that Canada has really interesting money.

You might already know that it’s made of plastic instead of paper, you might know that it has these see-through sections, which is really cool.

But the coolest thing about Canadian money is the maple leaf.

The maple leaf is see-through as well and it has a sort of frosted effect, but that frosting is actually really, really intelligent frosting. It’s a diffraction grating. You might have heard of diffraction gratings before, they are used in science to demonstrate the fact that light travels as a wave. Diffraction gratings are really important tool in science.

This diffraction grating has been built in such a way that if you shine a laser light through it, then projecting at the other side is the denomination of the note itself.

So, there you go, written around that central point of light is dollar one zero, dollar one zero, $10, $10. It used to be there was just the $100 bill that had this feature, but all denominations have it now. And if you don’t have access to a laser pointer don’t worry, instead you can look through the maple leaf at a point of light.

[Steve Mould:]Source: L Y B I O . N E T
And if you’re wondering what you can use as a point of light, look no further than your Christmas tree. If you look at your Christmas tree through the maple leaf of a Canadian note, you will see written around each of those Christmas tree lights the value of the note itself. And interestingly red lights have a longer wavelength than green lights and longer wavelengths are diffracted more than shorter wavelengths.

So when you see the value written around these points of light, they will appear larger around the red lights than they do around the green lights. And in fact, if you look at a white source of light through a bill of Canadian money, you will see its value written in rainbow colors.

So there you go, you can use Canadian money to demonstrate one of the most important ideas in quantum mechanics, the wave nature of light itself.